How to Complete the NYS Child Support Modification Petition (Form 4-11)

To change an existing New York child support order, file the NYS Child Support Modification Petition, Form 4-11, with the Family Court clerk in the county where your original order was issued. You can download the form from the New York State Unified Court System website, complete it with your case details and the reason you’re asking for a change, and submit it along with a Financial Disclosure Affirmation (Form 4-17) and supporting financial documents.¹ File as early as you can: any modification the court grants is retroactive to the date you filed the petition, not the date of your hearing.²

Do You Qualify to Modify

Before filling out anything, confirm you meet at least one of the three legal grounds New York recognizes. You only need one.³

A substantial change in circumstances. This is the broadest ground. An involuntary job loss, a serious medical condition, a child’s new special-needs diagnosis, or a significant change in custody can all qualify. A minor swing in overtime hours probably won’t. Incarceration counts as a substantial change, unless the sentence is for non-payment of support itself or for an offense against the custodial parent or the child.³
Three years since the last order. If three years have passed since the order was entered, last modified, or adjusted, either parent can seek a change without proving anything else. This applies automatically unless both parties opted out of it in a written stipulation.
A 15% change in either parent’s gross income. That alone is enough to file. If you’re asking for a reduction because your income fell, the drop must be involuntary, and you have to show you’ve made real efforts to find work matching your skills.

The three-year and 15% grounds can be waived by a valid written agreement. The substantial-change ground cannot.

Documents to Gather First

Pull these together before you sit down with the form. You’ll need them both to complete the petition and to bring to your hearing.⁴

Your existing support order, including the Docket Number and the date it was signed. If you’ve lost your copy, request one from the Family Court Clerk in the county that issued it.
The Financial Disclosure Affirmation, Form 4-17. This is a separate form you file alongside Form 4-11, detailing your income, expenses, assets, and liabilities.⁵
Income proof: recent pay stubs, your most recent W-2, and your latest federal tax return.
Benefits award letters if you receive Social Security, disability, workers’ compensation, unemployment, or veterans’ benefits.
Proof of childcare costs, health insurance premiums, and any extraordinary medical expenses for the child.
Any other support orders you pay or receive, with proof of payments.
The child’s birth certificate.
Any prior divorce judgments or stipulations.

Bring originals and copies. Missing a key document won’t automatically sink your case, but it can push your hearing back and weaken your position.

Filling Out Form 4-11

The petition is four pages, and most of it is checkboxes, names, and dates. At the top, fill in the county where you’re filing and the Docket Number from your existing order. Check the box indicating whether the original order came from Family Court or another court. Enter your name as the petitioner and the other parent’s full legal name as the respondent.¹

The section that matters most is the Statement of Facts. Tie your explanation directly to one of the three grounds. If you lost your job, give the termination date, your former employer’s name, and what you’ve done to look for new work. If your income changed by 15% or more, state your current earnings against what you earned when the last order was set. If you’re relying on the three-year ground, give the exact date of the prior order and do the math. Be specific. Vague explanations invite delays.

Toward the end, you specify what you’re asking for: an increase, a decrease, or another change to the terms. You can also request that the new order be retroactive to your filing date, which is your right under FCA § 440.²

Sign and date. The form does not require notarization; it has signature lines for you and your attorney if you have one, with no notary block. Form 4-17 is signed under penalty of perjury as an affirmation and likewise does not require a notary.

Filing the Petition

File Form 4-11, the completed Form 4-17, and your supporting documents at the Family Court Clerk’s office in the county where your original support order was issued. You can file at the clerk’s window in person. New York also offers the Electronic Document Delivery System (EDDS), which lets you upload PDFs to courts that don’t otherwise accept e-filing.⁶ If you use EDDS, your papers are not officially filed until the clerk sends you a notice of acceptance.

There is generally no filing fee for a child support petition. After the clerk processes your paperwork, the court issues a summons directing the other parent to appear at a scheduled hearing.

Serving the Other Parent

You cannot hand the summons and petition to the other parent yourself. Someone at least 18 years old who is not a party to the case has to deliver the papers.⁷ That can be a friend, a relative, or a professional process server. The New York City Sheriff’s Office also handles service for a fee.⁸

After service, the person who delivered the papers fills out an Affirmation of Service showing when, where, and how the respondent was served. File that affirmation with the court before your hearing date. Without proof of service, the case cannot move forward.

What Happens at the Hearing

A Support Magistrate handles your case. Support Magistrates have full authority to hear evidence, make findings, and issue support orders.⁹

At the initial appearance, the Magistrate reviews both parties’ financial disclosures. If you and the other parent can agree on a new amount, the Magistrate can approve it and enter an order that day. If you can’t agree, the case goes to a full hearing where both sides present evidence: pay stubs, tax returns, medical bills, childcare receipts, and testimony about what changed.

The Magistrate recalculates the obligation under the Child Support Standards Act, which applies fixed percentages of the parents’ combined income up to a statutory cap of $193,000 as of March 2026: 17% for one child, 25% for two, 29% for three, 31% for four, and no less than 35% for five or more.¹⁰ Above the cap, the Magistrate has discretion. The non-custodial parent’s share is proportional to their share of the combined income. The order will typically also address health insurance for the child, and can allocate unreimbursed medical costs, childcare, and educational expenses on top of the basic amount.

One place downward modifications often fall apart: imputed income. If the Magistrate finds you deliberately reduced your earnings to lower your obligation, whether by quitting, turning down promotions, or working part-time without good reason, the court can impute income based on what you previously earned or are capable of earning. Be ready to show your income drop was genuinely involuntary and that you’ve been actively looking for comparable work.

Retroactivity and Arrears

A modified order takes effect as of the date you filed the petition, not the date the Magistrate signs the new order.² If the hearing happens three months after you file and the court grants a reduction, you’ve been overpaying during those three months, and the difference is credited. If the court grants an increase, the higher amount applies back to the filing date, and the paying parent owes the difference as arrears.

Here’s the rule that makes timing critical: the court cannot reduce or cancel child support arrears that built up before you filed.³ Filing Form 4-11 protects you going forward from the filing date. It does not erase what you already owe. Every month you wait after your circumstances change is a month of arrears that can never be modified downward.

If You Disagree With the Order

You don’t appeal a Support Magistrate’s decision in the traditional sense. You file written objections with the Family Court judge. The deadline is 30 days after you receive the order in court or by personal service, or 35 days if the order was mailed to you.¹¹

Once you file and serve your objections, the other parent has 13 days to file a written rebuttal. The judge then has 15 days after the rebuttal deadline to remand the case back to the Magistrate, issue a new order, or deny the objections. The Magistrate’s order stays in full effect while objections are pending; there is no automatic stay.

One boundary worth naming: Form 4-11 modifies an existing support order. If your child has become emancipated, married, enlisted, or otherwise left parental control, that qualifies as a substantial change and you can use Form 4-11 to terminate support. If your existing stipulation defines its own emancipation triggers, those govern instead of the default rules, so read your agreement before you file.¹⁰

1
New York State Unified Court System. NYS Child Support Modification Form 4-11
2
New York State Senate. New York Family Court Act 440
3
New York State Senate. New York Family Court Act FCT 451 – Continuing Jurisdiction
4
New York Courts. New York City Family Court Child Support Information
5
New York State Unified Court System. Financial Disclosure Affirmation Form 4-17
6
New York State Unified Court System. Electronic Document Delivery System
7
New York Courts. How Legal Papers Are Delivered (Service)
8
NYC.gov. Serving a Child Support Summons
9
New York State Senate. New York Family Court Act 439 – Support Magistrates
10
New York State Senate. New York Family Court Act 413 – Parents Duty to Support Child
11
New York State Senate. New York Family Court Act FCT 439 – Support Magistrates